CORRECTION: Ref 628 is probably a 1962 catalogue, and not 1968. There's no date/year on that catalogue, and it appears reference numbers correlate to years, as seen in preceding catalogues, some of which are dated.
Sam Stevens asks "... a benelux star five speed (13-14-15-16-17 Teeth) and am trying to find out the date these came on the market ..."
There's no reference to a "Star" freewheel in these Cyclo Benelux catalogues:
1950 [Ref. 50]; 1953 [Ref. 538]; 1955 [Ref. 559]; 1960 [Ref. 609]; 1968 [Ref. 628/G/S]
Peter Brueggeman
La Jolla California USA
4peebee(at)peterbrueggeman.com